A comprehensive review published in Health Science Reports examines the efficacy and safety of COVID-19 vaccines in patients with multiple sclerosis (MS), providing guidance for clinicians managing vaccination in this population. The review, encompassing literature from January 2020 to July 2024, addresses key concerns such as vaccine efficacy, side effects, and the potential for relapse following vaccination.
The analysis focuses primarily on mRNA-based vaccines, including the BNT162b2 vaccine (Pfizer-BioNTech) and the mRNA-1273 vaccine (Moderna), as well as the viral vector vaccine AZD 1222 (AstraZeneca).
Impact of DMTs on Vaccine Response
A significant finding highlights the impact of disease-modifying therapies (DMTs) on vaccine response. The review notes a "notable reduction in the humoral response following COVID-19 vaccination" in patients receiving anti-CD20 therapies and sphingosine-1-phosphate (S1P) receptor modulators. While anti-CD20 therapies reduce antibody production, some T-cell responses remain intact, potentially offering partial protection. One study found a T-cell response after a third vaccine dose in some patients who did not achieve a humoral response, underscoring the importance of booster doses.
Clinical Outcomes and COVID-19 Severity
Clinical outcomes for MS patients with COVID-19 vary depending on their treatment regimen. Patients on anti-CD20 therapies or S1P receptor modulators have experienced more severe COVID-19 outcomes. A study by Sormani et al. indicated that MS patients on anti-CD20 therapies had "higher incidences of pneumonia, hospitalization, and severe complications compared to those on other DMTs." These findings were corroborated by Feuth et al., who reported prolonged viral pneumonia and increased mortality in anti-CD20-treated patients.
Vaccination Timing and Recommendations
Despite these complexities, the review emphasizes that COVID-19 vaccination is "a safer and more reliable approach to building immunity compared to becoming infected with the virus." The authors recommend delaying COVID-19 vaccination for at least 12 weeks after the last dose of anti-CD20 therapies to allow for a more robust immune response. Conversely, patients on interferons, teriflunomide, ofatumumab, natalizumab, dimethyl fumarate, glatiramer acetate, and S1P drugs do not require delayed vaccination. For cladribine, a delay of at least 4 weeks after the last dose is suggested, while in cases of lymphopenia, vaccination should be delayed until lymphocyte counts recover.
Safety and Side Effects
Live or live-attenuated vaccines are not recommended for MS patients who have recently taken steroids or are on certain DMTs, according to the National MS Society. Patients experiencing a relapse should delay vaccination until symptoms improve. Although some patients may experience an MS relapse after COVID-19 vaccination, research indicates that relapse rates after the first and second doses (2.1% and 1.6%, respectively) are similar to those in unvaccinated patients with MS, suggesting that vaccination does not significantly increase relapse risk.
Side effects of COVID-19 vaccines in MS patients are generally mild, including injection site pain, fatigue, and headache. Rarely, severe side effects have been documented with the viral vector vaccine AZD 1222 (AstraZeneca), such as deep vein thrombosis (DVT), myocarditis, pericarditis, and inflammatory neurological conditions like Guillain-Barré syndrome.
